• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.43-48
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• 2009

We constructed a simple wavelength readout system for a tunable fiber laser which was used for a fiber Bragg grating sensor array system. A quadrature sampling method was used to demodulate wavelength variations of the tunable laser which consisted of a SOA(semi-conductor optical amplifier) and a fiber-optic Fabry-Perot filter. Internal triggers, which have a 90 degree phase period, have been generated by using a double-pass Mach-Zehnder interferometer. From Lissajous plots with quadrature sampled data, a mean phase error of ${\sim}2.51$ mrad was obtained. From the wavelength readout experiments, an accurate and fast linear wavelength demodulation has been confirmed.

• Journal of Industrial Technology
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• v.26 no.A
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• pp.95-99
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• 2006

In this paper, we proposed the new wavelength tunable filter for wide tunability of fiber ring laser. The proposed filter consists of the cascaded connection of Fiber Reflection Mach-Zehnder Interferometer and Sagnac filter or of hybrid filter and Fiber Reflection Mach-Zehnder Interferometer. The simulation shows that the continuous tunable range of 50nm can be obtained and that more stable single mode operation of ring laser can be expected due to narrow FWHM. of filter spectrum.

• 전기의세계
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• v.50 no.9
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• pp.9-13
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• 2001

• Korean Journal of Optics and Photonics
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• v.9 no.4
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• pp.270-273
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• 1998

We have demonstrated the wavelength tunable ultrashort pulse fiber ring laser proposed the novel method for measuring the cavity loss from relaxation oscillation frequency and the pump power. To suppress the polarization instability the laser cavity is configured with polarization maintaining fibers and to control the center wavelength a 2.4 nm bandwidth tunable wavelength filter was inserted in the cavity. The laser has 8 picosecond pulse width, 10 GHz repetition rate and 1.2 mW average power in 1530-1560 nm operation range.

• Korean Journal of Optics and Photonics
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• v.10 no.5
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• pp.430-438
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• 1999

We have utilized soft-aperturing by gain media to develop a high-power tunable Ti:Sapphire laser with sub-40-fs and broad tuning range. The tunable spectral range was only limited by the bandwidth of mirrors. We made use of knife-edge slits near an intra-cavity prism controlled by micro-stepping-motors to tune the center wavelength continuously. The tunability of the center wavelength was ranged from 770 nm to 870 nm, and the measured pulsewidth was sub-40 fs throughout the above spectral range. The shortest pulsewidth was about 17 fs at the center wavelength of 820 nm and the spectral bandwidth was 72 nm. At 5 W pumping power of the Ar-ion laser we obtained average output power of 440 mW~580 mW. For the cw and Kerr-lens mode-lodking conditions, we have evaluated the value of an amplitude modulation to be ${\gamma}=2.5{\times}10^{-8}/W$ from the calculated waists of a Gaussian beam on the Ti:sapphire crystal surface. Using this result we demonstrate that the generation of sub-40-fs Kerr-lens mode-locked pulse can be described by the Ginzberg-Landau model which is a weak pulse shaping model.

• Korean Journal of Optics and Photonics
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• v.20 no.3
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• pp.189-194
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• 2009

We demonstrate a ring type wavelength swept laser incorporating a fiber Fabry-Perot tunable filter in a laser cavity using 1300 nm semiconductor optical amplifier as a gain medium. The output characteristics of the wavelength swept laser according to the applied scanning frequencies are analyzed in the temporal and spectral domain. The output of the wavelength swept laser decreases dramatically as the scanning frequency increases. And there is a significant peak power imbalance between the forward scan and the backward scan as the scanning frequency increases. Its use in practical applications might be limited.

• Korean Journal of Optics and Photonics
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• v.8 no.6
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• pp.450-455
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• 1997

A pulsed Ti:sapphire laser with a Z-folded cavity, which was pumped by a freqeuncy-doubled Nd:YAG laser, was developed. It shows 120 nm wavelength tuning range from 740 nm to 860 nm with 90 nm FWHM under a pumping energy of 3 mJ with 18% output coupler. Using a birefringent filter, the effective efficiency was improved about 10 times compare to without a birefringent filter. The output energy obtained was $\365mu$Jwith 4 nm FWHM. And the wavelength tuning range was broadened to about 160 nm within an output energy fluctuation of $\pm$10%.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.163-164
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• 2008

• Proceedings of the Optical Society of Korea Conference
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• 1996.09a
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• pp.66-66
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• 1996

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.123-123
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• 2013

OCT (Optical Coherence Tomography)는 의료용 생체조직의 단층 영상을 레이저 빛을 이용하여 구현하는 첨단 의료기술이다. Time-domain과 Fourier-domain을 기반으로 다양한 광간섭 신호의 획득이 연구되고 있으며, 영상획득 속도의 향상을 위한 경쟁이 세계적으로 치열한 상황이다. 최근 초고속 파장훑음 광원(Wavelength-swept source)의 개발을 통하여 초당 300 frame 이상의 단층 영상이 구현되고 있다. 본 발표에서는 초고속 파장훑음 레이저 광원(Wavelength swept laser)이 능동형 모드잠금(Active mode locking) 외부공진 반도체 공진 구조를 기반으로 새롭게 구현된 연구 성과를 포함한다. 분산에 의한 모드 잠금에 의하여 발진 파장이 결정되어 가변하므로 1 MHz 급 이상의 초고속 반복이 가능하며, 특히 의료용 산업용 분야의 다양한 광센서 및 광영상 응용에 활발히 응용되고 있다.